document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1119177>Question 1119177</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A medical researcher wishes to evaluate the effectiveness of a drug in prolonging the life of a red cell in a culture medium. Seven cultures are treated with saline (an inactive control substance) and seven others are treated with the new drug. The following survival times in days are recorded;<BR>\n" );
document.write( "Control Group      Treated Group<BR>\n" );
document.write( "129                       121<BR>\n" );
document.write( "102                       119<BR>\n" );
document.write( "138                       119<BR>\n" );
document.write( "126                       126<BR>\n" );
document.write( "121                       121<BR>\n" );
document.write( "100                       115<BR>\n" );
document.write( "113                       117<BR>\n" );
document.write( " <BR>\n" );
document.write( "Conduct the necessary test to determine if the treatment with the new drug does in fact prolong the life of a red cell. Use a  = 0.05. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #734891 by </B><A HREF=/tutors/aboutme.mpl?userid=Boreal><B>Boreal(15235)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=Boreal><IMG SRC=http://www.algebra.com/images/aboutme-small.gif BORDER=0 alt=\"About Me\" VALIGN=MIDDLE></A>&nbsp;<IMG SRC=http://www.algebra.com/cgi-bin/show-face.mpl?user=Boreal><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=734891\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> This is a 2 sample t-test.  Assume normality and variances may be considered homogeneous<BR>\n" );
document.write( "Ho: mu1>=mu2 or mu1-mu2>=0<BR>\n" );
document.write( "Ha: mu1< mu2 or mu1-mu2<0<BR>\n" );
document.write( "alpha=0.05<BR>\n" );
document.write( "test stat is a t 0.975, df=12<BR>\n" );
document.write( "critical value |t|<-1.782<BR>\n" );
document.write( "t= (mu1-mu2)/sqrt((s1^2)/(n1-1))+(s2^2)/(n2-1))<BR>\n" );
document.write( "t=(118.43-119.71)/sqrt((14.13/6)+(3.5/6))<BR>\n" );
document.write( "=-1.28/sqrt(2.355+0.583)<BR>\n" );
document.write( "=-1.28/5.94<BR>\n" );
document.write( "=-0.2155<BR>\n" );
document.write( "Fail to reject Ho at the 0.05 level. Insufficient evidence to say whether there has been a change.<BR>\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );